The present invention relates to an improved herbal composition having antiallergic properties, which is useful in the treatment of allergic conditions. The composition of the present invention is particularly useful for the treatment of allergic rhinitis, allergic bronchitis and bronchial asthma. This invention also relates to the process of preparing the antiallergic herbal composition.
One of the common diseases that affects humankind is xe2x80x98allergyxe2x80x99 in its diverse manifestations. Allergy refers to any condition of the body mounting an attack on a specific foreign substance. People can experience allergic reactions to foods, chemicals, plants, animals and a variety of air borne substances. The substance to which the person is allergic is called the allergen. Allergy refers to a condition where in there is manifestation of conditions such as asthma, rhinitis, urticaria, and dermatitis alone or in combination. In majority of the cases there is a familial tendency. In most of the allergic individuals, there is an increase in levels of circulating IgE antibodies (special class of Immunoglobulins). Allergy is defined as a hypersensitivity or hyperimmunity caused by exposure to a particular antigen (allergen) resulting in marked increase in reactivity to that antigen/allergen upon subsequent exposure. This exposure sometimes results in harmful immunological consequences. Some common allergens responsible for allergy are dust, pollen, house-mites, grass weeds, pets, fungal spores, dust, etc. Sometimes corn, egg, soya, peanut, milk chocolate, caffeine, etc can be a source of food allergy.
An allergy is a state of altered immune response. The immune system""s function is to identify and deal with the threats to the health. When a foreign body like dust or pollen enters the body, the exposure causes a reaction by the body. Usually the reaction itself is designed to rid the body of the allergens. This reaction can take many forms, one kind is an inflammatory reaction, the rushing of blood and/or mucus to the area of contact or site of invasion. This is healthy and normal. The increased blood supply to the affected area delivers healing nutrients, swelling, and heat may expel the invader and mucus may flush it out. Thus it acts as a protective phenomenon. But in the case of allergic individuals, this reaction persists for a longer time and causes inconvenience due to various clinical manifestations. An exaggerated defensive response by itself is the cause for this illness. A number of diseases like hay fever, bronchial asthma, urticaria and the like occur due to increased liberation of histamine or histamine like substances.
Headache, sneezing, watering of eyes, stuffy nose, wheezing and fatigue; these symptoms are the constant companions for an air borne allergy sufferer for several months (or more) every year. For those with perennial allergies, each day brings a cycle of misery, often broken only temporarily by powerful drugs like anti histaminics, steroids to suppress the immune system and decongestants, often with side effects like drowsiness etc. Air borne allergies usually affects the respiratory system. It involves sneezing, itching of throat and eyes, sinus headaches and sometimes coughing. Tree pollens, grass, weed pollens, pets, moulds, fungus, dust and cigarette smoke are common household allergens that can cause the allergic symptoms.
On exposure to an antigen (allergen), special type of cells called antigen presenting cells carry the antigen, process it and present it to special type of white blood cells called T-lymphocytes [TH2 subset of CD4+T helper lymphocytes]. These T-lymphocytes respond by releasing important chemical mediators called cytokines like interleukins IL4, IL5, IL6 and granulocyte-macrophage colony stimulating factor (GM-CSF). The cytokines interact with B-lymphocytes (white blood cells) present in lymph nodes. The B-lymphocytes transform themselves into plasma cells, which secrete IgE antibodies. These are specific to the antigen. Once formed, the IgE antibodies have a strong tendency to get attached to a special group of cells called mast cells and basophils. Mast cells are located on the skin, Lung mucosa, bronchial mucosa, intestinal mucosa, lymphnodes, breast parenchyma and liver. They play a vital role in allergic and inflammatory phenomenon. A mast cell is a storehouse of 15-20 chemical mediators, which is responsible for clinical manifestations of allergy. On reexposure to allergen (antigen), the preformed IgE antibody on mast cell reacts with the antigen. The combination evokes a series of changes at the molecular level, which ultimately release the following mediators:
1) Histamine
2) 5-Hydroxytryptamine (Serotonin)
3) Leucotrienes B4, C4, D4, E4 
4) Platelet activating factor
5) Prostaglandin D2 
6) Interleukinsxe2x80x94IL-3, IL-4, IL-5, IL-6, Granulocyte macrophage colony stimulating factor (GMCSF), IL-1
7) Tumour necrosis factor-xcex1(TNF-xcex1)
8) Bradykinin etc.
Of all these mediators Leucotrienes C4 and D4 are the most potent vasoactive (capable of acting on blood vessels) and spasmogenic agents known. They increase the vascular permeability and cause vasodilatation and bronchial smooth muscle contraction. LTB4 causes chemotaxis of neutrophils and eosinophils (white blood cells) which cause release of prostaglandin and bring about inflammatory changes. Prostaglandin PGD2 causes broncospasm and increases mucus secretion. PAF (Platelet activating factor) causes platelet aggregation, release of histamine, broncospasm, increased vascular permeability and vasodilatation. It also acts as chemotactic for neutrophils and eosinophils. Therefore, it is important in late phase of inflammation. Cytokines like TNF, IL1, IL3, IL4, IL5, IL6 and GM-CSF are important cytokines that recruit inflammatory cells, which further cause degranulation. TNF-xcex1 is extremely important for attracting the cells at the site of inflammation.
Allergy is characterised by two distinct phases, the immediate phase and the delayed phase. The immediate phase includes the initial response that lasts for first 1-2 hours characterised by
i) Vasodilatation, i.e. engorgement of the blood vessels that line the mucous membrane of the nose and
ii) Vascular leakage i.e. escape of plasma with proteins from the blood vessels. The mediators responsible are histamine and leucotrienes.
The delayed phase is the cellular phase or the inflammatory phase mediated by PAF, TNF, leucotrienes. On reexposure to allergen the preformed IgE antibody on mast cell reacts with the antigen. Unlike the protective inflammatory response in case of infections or any other trauma the phenomenon in case of allergy is different in that it is not self-limited. Antigen antibody reactions occur as long as the person gets exposed to allergen and as long as these reactions occur, the inflammation has to set in. As a result, the various effects of the cellular phase i.e. release of enzymes, free radicals, prostaglandins etc will continue to persist and cause persistent tissue damage, which eventually leads to chronic inflammation. Hence, a check is necessary. The main difference between allergy prone and non-allergy prone individuals is allergy prone individuals have been found to have an elevated IgE levels which means they over respond to antigenic stimulation unlike the other individuals. Further,
i) The tendency for susceptibility is inherited.
ii) There is a deficiency of intracellular control of mediator release or synthesis or both or possibly, extra cellular control signals that generally bring mediator inactivation are impaired.
For more details, reference may be made to Robbins: Pathologic Basis for Disease, 5th Edition 1994 W.B Saunder Company., Harrisons"", xe2x80x9cPrinciples of Internal Medicinexe2x80x9d. 14th Edition, McGraw Hill Publications, 1998.
Allergic rhinitis is a chronic inflammation of the mucus membrane lining the nasal passages that is caused by an allergic reaction. It is characterised by a stuffy, runny nose, frequent sneezing and a tendency to breathe through the mouth. Eyes may be red and watery. Headache, itchiness, nosebleeds and fatigue may be secondary complications. Some of the reasons for this condition could be exposure to wool, molds, feathers, dust and pollen etc.
Features of allergic rhinitis are:
1. Could be seasonal or chronic
2. Family history is often present
3. Increased levels of circulating IgE antibodies in such patients
The present day therapy of allergic rhinitis includes:
Prevention of contact with allergen
Supportive therapy with anti-histaminics, decongestants, mast cells stabilizers and anti-inflammatory agents like corticosteroids.
Definitive therapy includes identification of the cause by intra-dermal injections of allergen and subsequent desensitization of the individual once the cause/allergen has been identified.
Despite having all the above therapies the cure for allergic rhinitis by the above related treatment is far from satisfactory. The process of desensitization is also expensive and complicated, requiring support of the patient with limited success. Hence, there is a need for alternative therapy.
Bronchial asthma is actually improperly called reactive airway disease. It is usually an allergic response, some times to the same allergens that cause hay fever, and is often exacerbated by stress, exercise, infection, fumes, and cold air. It is characterized by symptoms like coughing, wheezing and breathlessness. These symptoms of an attack are caused by the contraction of smooth muscle of bronchial airways and by secretion of mucus that blocks the airway. Asthma is a disease of respiratory tract that causes breathing problems. These problems usually happen in episodes, also called attacks. Asthma is usually a chronic problem i.e., people who have asthma live with it everyday often for their whole life. It is serious, and it can be life threatening if not properly managed. However, with proper management most people with asthma can live normal, productive lives. Several factors have been suggested, such as an exposure to infections, and other triggers of allergens, and the quality of the air we breathe out doors and indoors. An asthma attack typically occurs when an allergen or irritant affects the sensitized lungs. Everyday life is filled with the allergens and other precipitating factors that can kick off an attack.
For example
Allergens: Pollens, feathers, moulds, animals, some foods, house dust.
Infections: Common cold, influenza.
Emotional stress and excitement.
Vigorous exercise.
Cold air.
Occupational dusts and vapors: Plastics, grains, metals, wood.
Air pollution: Cigarette smoke, ozone, sulphur dioxide, auto exhaust.
Sleep (nocturnal asthma).
Household products: paint, cleaners, sprays.
Drugs: aspirin, heart medications etc.
For more details, reference may be made to xe2x80x9cThe Johns Hopkins Medical Handbookxe2x80x9d (1992) Published by Rebus, INC. New York.
Intense research during the last several decades has highlighted the role of lymphocytes, immunoglobulin, mast cells and various autocoids in the pathogenesis of allergic conditions. Treatment of acute manifestations is limited to the use of adrenergic agents and adrenocorticoids for symptomatic relief. Antihistamines have limited utility. Isolated cases benefit from desensitization procedures, if the allergy is against a simple allergen. Various products have been used for the treatment of allergic conditions.
Presently some of the following therapies are used for the treatment of asthma/allergic bronchitis:
1. Bronchodilators like salbutamol, theophylline, which cause bronchial relaxation and reduce wheeze.
2. Anti histaminics like cetrizine, chlorpheniramine maleate etc., which block the effects of histamine on bronchial smooth muscle.
3. Corticosteroids which cause a reduction in immune mechanisms and act as anti-inflammatory agents.
4. Mast cell stabilizers like disodiumchromoglycate and ketotifen, which prevent the release of mediators from mast cells.
5. Supportive antibiotics as and when required, since infection can trigger or follow allergic bronchitis.
However, there are reports that prolonged using of these products can be harmful.
Each of these are having following restrictions.
Contraindications
Special precautions
Interactions highlighting potential hazards
Food interactions
The adverse effects encountered with the above mentioned therapies are the following:
1. Bronchodilatorsxe2x80x94Salbutamol causes muscle weakness, tremors, hypokalemia, tachycardia etc. Theophylline has a narrow therapeutic index and can cause tachycardia, precardial pain etc.,
2. Antihistamanicsxe2x80x94Cause sedation, tachycardia etc.
3. Corticosteroids:xe2x80x94Prolonged inhalation can cause oral thrush. Systemic absorption on long time oral medication can cause gastritis, osteoporosis, edema etc.,
4. Disodiumchromoglycate can cause cough wheezing, laryngeal edema headache rash etc.
For more details reference may be made to:
1. Harrisons"", xe2x80x9cPrinciples of Internal Medicinexe2x80x9d. 14th Edition, McGraw Hill Publications, 1998.
2. Martindales The Extra Pharmacopoeia, 30th Edition 1993.
3. Goodman Gillman""s xe2x80x9cThe Pharmacological basis of Therapeuticsxe2x80x9d Mc Graw Hill, Newyork. Edition: Alfred Goodman Gillman, Theodore W. Rall, Alan S. Nies Palmer Jaylor. McGraw Hill Publications, 1991.
There are known herbal preparations described in ancient books which are useful in general, but are not meant specifically for allergy and asthma. In other words, these known preparations are used for variety of diseases. Further such preparations are used in crude forms, require high dosage, non palatable taste, and inconvenient dosage forms. In the case of certain other herbal preparations the efficacy of such preparations are not very well established.
In the present day, herbal products have become very popular because of their effectiveness along with minimum risk of side effects as compared to the synthetic products. Consequently research work based on various herbs for developing products for treating various diseases is in progress all over the world.
As explained above the synthetic products presently used for the treatment of allergic conditions have a good amount of side effects. An antiallergic product will be potent if it can modulate the immune system and reduce the sensitivity of the individual in such a way that less IgE secretion occurs and even if it occurs, the mast cells are stabilized.
The herbal kingdom offers few remedies for allergy. In natural therapy, certain herbal preparations were given mainly to boost the immune system of the body thinking that the altered immunity is the reason for allergy. However, the satisfaction of the patient was very low and these products use to seldom give appreciable relief. Owing to these reasons they never became popular with the patients.
The main objective of the present invention is therefore to provide an improved composition having profound antiallergic activity.
Another objective of the present invention is to provide an improved composition having anti allergic properties, which not only provides relief particularly in allergic rhinitis, allergic asthma and allergic bronchitis but also helps in correcting the underlying immunological disorders.
Still another objective of the present invention is to provide an improved herbal based composition having anti allergic properties which controls allergic manifestations like sneezing, stuffy nose, watering of eyes, itching in throat, eyes and nose, wheezing, breathlessness etc.
Another objective of the present invention is to provide an improved herbal composition having antiallergic properties, which does not cause drowsiness or immune separation unlike other chemical anti allergic compounds.
Another objective of the present invention is to provide an improved herbal composition having anti allergic properties which acts by mast cell stabilization i.e. by preventing the release of histamine which is responsible for manifestation of allergy. Still further objective of the present invention is to provide a process for the preparation of an improved herbal composition having anti allergic properties
The present invention is based on our experience and knowledge about the usage of various herbs along with our in depth studies on traditional literature. For this project a number of plants and plant preparations were selected for detailed studies. The selected plants/extracts were then subjected to the mast cell stabilization bioassay. This bioassay has been reported to be one of the important tools in detecting the substances having antiallergic activity. In this context reference may be made to xe2x80x9cRajashekharan M. et al, J. Drug Dev., 1989, 2(3), 179-182.xe2x80x9d Mast cells are basophilic cells in subcutaneous and connective tissue. They are found in large numbers in mesentery of rats and contain numerous membrane bounded granules, which contain strong pharmacologically active mediators such as histamine, SRS-A, Serotonin, bradykinin etc. The role of mast cells in pathogenesis of allergic disease has been well recognized. Mast cells contain receptors for Fc fragment of IgE antibodies. Therefore, IgE antibodies formed on exposure to antigen will combine with the mast cells. On subsequent re-exposure to the same antigen, there occurs an antigen antibody reaction which will initiate mast cell de-granulation in a similar manner as that of de-granulating agents like carbachol or the compound which is the condensation product of N-methyl-p-methoxyphenylamine with formaldehyde. In this context reference may be made to Das S. N. et al. Ind. J. Indigenous. Medicine, April-September 1995; 17(1): 79-82.
Amongst the several plant extracts/plant fractions tested, we found that the following plants gave interesting results in the mast cell stabilization assay:
Our sustained research and studies based on the above results revealed that extracts of the plants having EC50 values of more than 500 mcg/ml are not generally useful for antiallergic applications. Hence such plants were excluded from further research. From the above results it was also very clear that the extracts of Terminalia chebula, Terminalia bellerica, Piper longum, Piper nigrum, Albizia lebbeck, Albizia chinensis, Zingiber officinale, and Emblica officinalis, show promising mast cell stabilizing activity. Based on our above said findings we selected the above mentioned plants for the development of the present invention. Subsequent to the above said biological evaluation each of the extracts of the above said selected plants were analysed chemically. It also became clear from our studies that tannin bearing plants like Terminalia chebula, Albizia lebbeck, Terminalia bellerica, Emblica officinalis, Albizia chinensis show better activity when extracted with water while plants like Piper longum, Piper nigrum and Zingiber officinale show better activity when extracted with alcohol.
All the above mentioned plants which were short listed for developing the present invention have been well known in Ayurveda but their extracts in synergistic combinations having anti allergic activities, is hitherto not known and hence is novel. Given below are the information which are available in public domain on each of the selected plants used for the development of the present invention.
1) Terminalia Chebula 
Part used: Fruits
Botanical description: Moderate or large deciduous tree, attaining a height of 25 to 30 mts. Leaves are 7 to 20 cms, glabrous, opposite, elliptic, oblong, rounded with acute apex. Flowers are bisexual and white or yellow in colour. Fruit is a drupe, pendulous, 2-4 cm long, obovoid from a broad base, glabrous. (Wealth of Asia, NISCOM, D-2.3, CSIR, New Delhi, 1996.)
Medicinal uses: Haritaki (Terminalia chebula) is an effective astringent and gargle for ulcerated surfaces, rejuvenative, tonic, laxative, nervine, expectorant and anthelmentic. It is indicated in cough, asthma, hoarseness of voice, hiccups. Fruits were used to treat cold along with pista, cloves and honey. Fruit powder is used in treating cough and asthma. (Wealth of Asia, NISCOM, CSIR, New Delhi, 1996; K. L. Bhishakratna, Susrutha Samhitaxe2x80x94Uttara tantra p. 118-130; Mokhasmit, M. et al., U.J. Med. Assocn. Thailand, 1971, 54(7), 490-504; Reddy, M. B. et al., Ind. J. Crud. Drug Res. 1989, 27(3), 145-155; Azeem M. A. et al. Fitoterapia, 1992; 63(4): 300-303; Reddy, B. M., et al, Int. J. Pharmacogn., 1994; 32(4), 352-35; Yogaratnakara, Chaukamba Pub., p. 320-330; Bhavaprakasha with Vaidyotini Commentary by Misra, B. S, xe2x80x9cChikitsa Prakarana madhyama khandaxe2x80x9dxe2x80x94Chaukamba Pub, 1980; p. 683-701.
Phytochemistry: Fruits contain about 30% of astringent substancesxe2x80x94chebulinic acid, tannic acid, gallic acid etc., resin and purgative principles of the nature of anthraquinones and sennosides are also present (Wealth of Asia, NISCOM, D-2.3, CSIR, New Delhi, 1996.).
Hydrolysable tannins like terchebulin, punicalagin and terflavin-A and phenolics like gallic acid, chebullic acid, di-ethyl ester of chebulic acid and ethyl ester of gallic acid have been reported to be isolated from fruits (Rastogi, R. P. et al, Compendium of Indian Medicinal Plants, 1991, Vol. 2, p. 671).
Pharmacology: It has been reported to exhibit antitussive and antihistaminic properties and has been used for bronchial asthma and chronic sinusitis. Its laxative property is used to treat constipation. Nutritive value of the chebulic myrobalan (Terminalia chebula) and its potential as a food source has been evaluated. The water and ethanolic extracts of the fruit on guinea pig ileum at a concentration of 0.01 gm/ml were found to have strong antihistaminic activity. (K. L. Bhishakratna, Susrutha Samhitaxe2x80x94Uttara tantra, p. 118-130; Dhawan, B. N. et al. xe2x80x98Screening of Indian Plants for Biological Activityxe2x80x99, Ind. J. Exp. Biol., 1968; 232-247; Mokhasmit, M. et al., U. J. Med. Associ., Thailand, 1971; 4-57: 49-50; Tripathi, Y. N. et al., Sachitra Ayur., 1983; 35(11): 733-740; Bharatkar, N. N. et al., Food Chemistry, 1991, 40(2), 213-219).
2) Terminalia Bellerica 
Part used: Fruits
Botanical Description: A very large tree, with an erect trunk and large spreading head, flowering in the hot season, leaves crowded about the extremities of the branches, long petioled, oval to obvate or shortly acuminated, quite entire glabrous above and generally also beneath, 6 to 7 inches long by 2xc2xd board, with 2 opposite glands on the upper side of the apex of the petiole and some times near the base, spikes axillary solitary simple erect almost the length of the leaves, flowers creamy white, the male towards the apex of the spike and shortly pedicellate, stamens 10, filaments 2-3 mm long, 8-12 cms long axillary spikes with a glandular disk at the bottom of the calyx, hermathrodite below and sessile ovary unilocular, two ovuled style 3-4 mm long, drupe obovate obscurely 5-angled, the size of a nutmeg, fleshly, brown pubescent. (Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi, 1996.)
Medicinal use: It is employed in dropsy, piles, diarrhoea and leprosy; also occasionally in fever. When half-ripe it is used as a purgative due to the presence of oil that has properties similar to those of castor oil. On hydrolysis, the oil yields an irritant principle. (Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi, 1996; Kirtikar and Basu, Vol-II, 1018-1019, Yogaratnakara, Chaukamba Pub., p. 320-330; Bhavaprakasha with Vaidyotini Commentary by Misra, B. S, xe2x80x9cChikitsa Prakarana madhyama khandaxe2x80x9d, Chaukamba Pub, 1980; p. 683-701.)
Phytochemisty: The fruits contain about 20 to 30% of tannins and 40 to 45% water-soluble compounds. The constituents include a green fixed oil, saponins, a resinous residue and three amorphous, hygroscopic glycosidal compounds and colouring matter. Tannins like phyllemblin, bellericannin, chebulagic acid and phenolics like gallic acid, ellagic acid, ethyl gallate have also been reported to be present in the fruits. The fixed oil contains esters of palmitic, stearic, oleic and linoleic acids. Triterpenes like belleric acid along with its glucoside bellericoside has been isolated from the fruits. (Kokate, C. K., Pharmacognosy, Nirali prakashan Pub., Pune, p. 323-324; Row and Murthy, xe2x80x9cChemical Examination of Terminalia bellericaxe2x80x9d, Ind. J. Chem., 1970, 8, p.1047).
Pharmacology: Crude powder of the fruit is used for antitussive and antiasthmatic activity. The maximum tolerated dose of fruit extract was found to be 1000 mg/kg i.p. in mice. (Dhar et al. Indian J. med. Res., 1969, 57, p.103; Trivedi, V. P et al., xe2x80x9cClinical study of the anti-tussive and anti-asthmatic effect of Vibhitakphal churna (Terminalia bellerica) in the cases of Kasa-swasaxe2x80x9dJ. Res. Ayur. Siddha, 1985, 3(142), p.1-8; Mokhasmit, M. et al. U.J. Med. Ass., Thailand, 1971, 54(7), p.490-504.)
3) Emblica Officinalis 
Synonym: Phyllanthus emblica 
Part used: Dried fruit
Botanical description: A small to medium sized deciduous tree, 8-18 meters height with thin light grey bark exfoliating in small thin irregular flakes, leaves are simple, sub-sessile, closely set along the branchlets, light green having the appearance of pinnate leaves; flowers are greenish yellow, in axillary fascicles, unisexual, males numerous on short slender pedicels, females few, sub-sessile, ovary 3-celled; fruits globose, fleshy, pale yellow with six obscure vertical furrows enclosing six trigonous seeds in 2-seeded 3 crustaceous cocci. (The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi, 1996).
Medicinal uses: The fruits are sour, astringent, bitter, acrid, sweet, cooling, anodyne, ophthalmic, carminative, digestive, stomachic, laxative, alterant, aphrodisiac, rejuvenative, diuretic, antipyretic and tonic. They are useful in vitiated conditions of tridosha, diabetes, cough, asthma, bronchitis, cephalalgia, ophthalmopathy, dyspepsia, colic, flatulence, hyperacidity, peptic ulcer, erysipelas, skin diseases, leprosy, haematogenesis, inflammations, anemia, emaciation, hepatopathy, jaundice, strangury, diarrhoea, dysentery, hemorrhages, leucorrhoea, menorrhagia, cardiac disorders, intermittent fevers and greyness of hair. (The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi, 1996; Indian Medicinal Plantsxe2x80x94A compendium of 500 species, Part 3, Orient Longman Publications, 1997, page 256-263; Shastry V. D., Bhavaprakasha Nighantu, Motilal Banarasidas Publication, 1988, page 9; Nadkarni K., Indian Materia Medica, Popular Prakashan, 1993 Vol. 1, p. 480.)
Pharmacology: The fruit extract has been tested for their expectorant activity and the activity was found to be due to direct stimulation of bronchial glands. The product is not reported to have any side effects even after prolonged use. (Nadkanmi K. M. Indian Muteria Medica, Vol. 1, Popular Prakashan, 1993, p. 480; Khorana, M. L. et al., J. Sci. Industr. Res., 1960; 19(C): 60-61; Deka, A. et al., Ancient Science of Life. 1983, 3(2),108-115).
Phytochemistry: The fruits of Emblica officinalis are rich in tannins. The fruits have 28% of the total tannins distributed in the whole plant. The fruits have been reported to contain two hydrolysable tannins Emblicanin A and B, which have antioxidant properties, one on hydrolysis gives gallic acid, ellagic acid and glucose wherein the latter gives ellagic acid and glucose. Phyllemblin, Punigluconin Pedunculagin, were also reported to be isolated from fruits. The tannins are having the molecular weight ranging from 750-850. Apart from L-ascorbic acid, Emblica fruits also contain xe2x80x98ascorbigenxe2x80x99, an indole containing derivative of L-ascorbic acid (Vitamin C). Ascorbigen and its derivative N-methylascorbigen represent a new class immunomodulators. (The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi, 1996; Jaiswal, K. S. et al., J. Sci. Industr. Res., 1959; 18(9): 180-181; Bose B. C. et al., Ind. J. Med. Sci, 1961; 15: 888; Ghosal S. et al. xe2x80x9cActive constituents of Emblica officinalisxe2x80x94Part 1, The chemistry and anti-acidity effects of two new hydrolysable tannins, Emblicanninxe2x80x94A and B,xe2x80x9d Ind. J. Chem., 1996, Vol. 35B, pg. 941-948.
4) Piper Longum 
Part Used: Fruits
Botanical Description: A slender aromatic climber, rooting at the nodes, the branches erect, subscandent, swollen at the nodes; leaves alternate, lower ones broadly ovate, cordate, upper ones oblong, oval, all entire, smooth, thin with reticulate venation, veins raised beneath; flowers in solitary spikes; fruits berries, small, red when ripe, completely sunk in solid fleshy spike. (The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi, 1996).
Medicinal use: The fruits as well as roots are attributed with numerous medicinal uses, and are used for diseases of respiratory tract, viz., cough bronchitis, asthma, etc. It is used as a counter-irritant and analgesic when applied locally for muscular pains and inflammation; as snuff in coma and drowsiness and internally as carminative; as sedative in insomnia and epilepsy and as general tonic and haematinic (The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi, 1996).
Pharmacology: Rhizomes of Zingiber officinale and leaves of Adhatoda vasica along with fruits of Piper longum is used to treat bronchial asthma. Dried Fruit mixed with honey are used to treat cough and generally used for cold as a home remedy. (The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi, 1996; Satyavati, G. V. et al. Medicinal Plants of India, ICMR, New Delhi: 1987; Vol-2, p. 426; Dhar et al., Ind. J Exp. Biol., 1968, 6, 232; Reddy M. B. et al., xe2x80x98A Survey of Plant crude drugs in Anantpur district, Andhra Pradesh. Indiaxe2x80x99, Int J Crude Drug Res., 1989, 27(3), 145-155). In view of the therapeutic use of Piper longum in bronchial asthma by Ayurvedic physicians, studies have been carried out on the mechanism of its anti allergic effects, as milk extract effectively reduced passive cutaneous anaphlylaxis in rats and protected guinea pigs against antigen induced bronchospasm. (Dahanukar, S. A., et al. xe2x80x98Piper longum in childhood asthmaxe2x80x99, Indian Drugs, 1984, 21, 384; Dahanukar, S. A et al. xe2x80x9cEvaluation of Antiallergic activities of Piper longum,xe2x80x9d Indian Drugs, 1984, 21, 377-380). Piper longum has been advocated for prophylactic treatment of asthma in Indian traditional medicine. It was shown highly effective in decreasing frequency and severity of attacks in childhood asthma. In addition, sensitivity test, serum IgE and pulmonary functions all showed significant improvement after treatment with Piper longum. 
The fruits are attributed with numerous medicinal uses, and may be used for diseases of respiratory tract viz., bronchitis, asthma (The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi 1996). Evaluation of antiallergic activities of Piper longum is carried out by rat lung perfusion (Sunanda et al., Proceedings of 13th Annual Conference Indian Pharmacological Society, 1981). In case of bronchial asthma, significant effect in controlling the frequency and severity of the asthmatic attack was observed. (lesnanduz et al., Pediatric Clinic, India, 1980; 15(4): 45.
Phytochemistry: The fruits contain 1% volatile oil, resin, alkaloids piperine and piperlonguminine, a waxy alkaloid N-isobutyldeca-trans-2-trans-4-dienamide and a terpenoid substance. (Atal, C. K. et al., Ind. J. Pharm., 1964; 26: 80).
5) Piper Nigrum 
Part used: Fruits
Piper nigrum is used widely as a household spice. Several studies have reported enhancement of blood levels of drugs when co-administered with Piperine. It was recognized that altered drug effects arise as a consequence of a change in bioavailability. In Indian medicine it is much employed as an aromatic stimulant in cholera, weakness following fevers, vertigo etc as a stomachic in dyspepsia and flatulence, as an anti periodic in malarial fever and as an alternative in paraplegia they are useful in arthritis, asthma, fever, cough, catarrh, dysentery, flatulence, cough.
Botanical Description: A climbing perennial shrub. Branches are stout, trailing and rooting at the node. Leaves entire, variable in breadth, 12.5-17.5 cm by 5.0-12.5 cm. Flowers are minute in spikes, usually dioecious, often female bears 2 anthers and the male, a pistillode. Fruiting spikes are variable in length. Fruits are globose and bright red when ripe and it is described as drupe, seeds usually globose. (The Wealth of Asia, NISCOM, D-2.3. C.S.I.R., New Delhi 1996).
Medicinal use: In Indian medicine, it is much employed as an aromatic stimulant, in cholera, and in weakness following fevers, vertigo, coma, etc., as a stomachic in dyspepsia and flatulence, as an antiperiodic in malarial fever. It is also used as an alterative in paraplegia and arthritic diseases. Externally, it is valued for its rubefacient properties and as a local application for relaxed sore throat, piles and some skin diseases. (The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi 1996, Yogaratnakara, Chaukamba Publications., p. 320-330; Bhavaprakasha with Vaidyotini Commentary by Misra, B. S; Chikitsa Prakarana madhyama khandaxe2x80x94Chaukamba Publications, 1980, p. 683-701; Sharma P. V., Charaka Samhitaxe2x80x94Chikitsa Stana, Chaukamba Publications, 1996; p. 434-447).
Pharmacology: It has anti-allergic activity. Piperine strongly inhibits hepatic arylhydrocarbon hydroxylase and UDP-glucuronyl transferase activities, thus prolonging hexabartital sleeping time and zoxazolamine paralysis time in mice. Piperine enhanced the bioavailability of oxyphenylbutazone and thereby potentiated its anti-inflammatory activity in rats. (Kholkute, et al., Ind. J. Exp. Biol., 1979; 17 289-290; George et al., J. Sci. Ind. Res., 1947, 6B, 42; Satyavati, G. V., xe2x80x9cMedicinal Plants of Indiaxe2x80x9d, ICMR, New Delhi. 1987; 2: 426; Dhar et al. Ind. J. Exp. Biol., 1968; 6, p.232; Majumdar, A. M. et al., xe2x80x9cEffect of piperine on bioactivity of oxyphenylbutazone in ratsxe2x80x9d, Indian Drugs, 1999; 36(2), 123-126)
Phytochemistry: Pepper contains volatile oil, the crystalline alkaloids, piperine, piperidine, piperettine and a resin. The minor alkaloids present are piperitine, piperolein A, piperolein B, piperanine, trichostachine. The volatile oil contains large amounts of terpenes, and a xcex1-pinene, phellandrene, dipentene and sesquiterpenes. The pungency is ascribed to piperine and the resin. They do not have any of the alkaloids and isobutyl amides found in the fruit (Atal, C. K. et al., Lloydia, 1962; 38: 256; Jennings, W. G. et al. Food Science, 1962; 26: 499; Sridharan K. et. al., J. Res. Ind. Med. Yoga Homeo, 1978; 13: 4).
6) Zingiber Officinale 
Part used: Rhizome
Family: Zingiberaccae
Botanical description: A herbaceous rhizomatous perennial, reaching up to 90 cm in height under cultivation. Rhizomes are aromatic, thick lobed, pale yellowish, bearing simple alternate distichous narrow oblong lanceolate leaves. The herb develops several lateral shoots in clumps, which begin to dry when the plant matures. Leaves are long and 2-3 cm broad with sheathing bases, the blade gradually tapering to a point. Inflorescence solitary, lateral, radical, pedunculate oblong-cylindrical spikes. Flowers are rare, rather small, calyx superior, gamosepalous, three toothed, open splitting on one side, corolla of three subequal oblong to lanceolate connate greenish segments. ((The Wealth of Asia, NISCOM, D-2.3, C.S.I.R., New Delhi 1996).
Traditional use: Ginger is carminative, pungent, stimulant, used widely for indigestion. It is chiefly used to cure diseases due to morbidity of Kapha and Vata. Ginger with lime juice and rock salt increases appetite and stimulates the secretion of gastric juices. It is said to be used for chronic bronchitis, common cold, chest congestion, cough, difficulty in breathing, dropsy, sore throat, throat ache, stomach ache, vomiting and rheumatism. Ginger forms an important constituent of many pharmacopoeial Ayurvedic formulations. (Misra B, Bhavaprakasha Nighantu, 5th edition, 1969, p.14; Sharma P. V. Dravyagunavignani, Part II, Chaukamba Publications, 1993, p. 331; Indian Medicinal Plants, A Compendium of 500 species, Part V, by Orient Longman Publications, 1997, p. 431; Nadkarni, Indian Materia Medica, Vol. I, 1993, p.1308; Yogaratnakara, Chaukamba Publications, p.320-330; Bhavaprakasha with Vaidyotini Commentary by Misra, B. S; Chikitsa Prakarana madhyama khandaxe2x80x94Chaukamba Publications, 1980; p. 683-701.
Phytochemistry: Ginger has been reported to contain usually 1-3% of volatile oil, pungent principles viz., gingerols and shogaols and about 6-8 lipids and others. Ginger oil contains zingiberene and bisaboline as major constituents along with other sesqui and monoterpenes. Ginger oleoresin contains mainly the pungent principles gingerols and shogaols as well as zingiberone. Shogaols have recently been found twice as pungent as gingerols. (Kiuchi F, et al., Chem. Pharm. Bull, 982, 30, 754; Wagner H, et al, Plant Drug Analysis, Springer, 1996, 300; Akhila A and Tewari. CROMAP, 1984, 6(3), 143-156).
Pharmacology: It is used for common colds due to pathogenic wind cold, characterized by severe intolerance to cold, slight fever, headache, general ache, nasal congestion and a running nose. Antihistamine activity has been studied in ginger. Zingiber officinale was indicated in allergic conditions in traditional text. However, they were following crude methods. Toyoda J., xe2x80x98Antihistamine substance from gingerxe2x80x99, Chem. Abst., 1969, 71, 33425; Yogaratnakara Chaukamba Publications, p.320-330; Bhavaprakasha with Vaidyotini Commentary by Misra, B. S; Chikitsa Prakarana madhyama khandaxe2x80x94Chaukamba Publications, 1980; p. 683-701.
7) Albizia Species: For Example Albizia chinesis, Albizia lebbeck 
Part Used: Bark
Botanical description: It is a large, erect, unarmed, deciduous, spreading tree common all over India. It is found in the plain up to 900 m in the Himalayans and in the Andamans. Also known as the East Indian walnut or Sirish (Hindi). The tree prefers moist situations and is found to grow on a number of soils. (The Wealth of Asia, is NISCOM, D-2.3, C.S.I.R., New Delhi, 1996).
Medicinal use: Albizia species are known plants in the literature of Indian medicine, for diseases like bronchial asthma, utricaria and insect bites. The protective action of the Albizia species on adrenals against histamine is established which can be favorably utilized for the treatment of bronchial asthma and other allergic disorders. (The Wealth of Asia, NISCOM, D-2.3,., C.S.I.R., New Delhi, 1996; Tripathi S. N. et al., Quart. J. of Surgical Science, 1978, March-June, p.170-176; Shah and Bhattacharyya, J. Sci. Industr. Res. 1960, 19C, p.199; Farooqi and Kaul, ibid, 1962, 21B, p.454; Chakravarty, Bull. Bot. Soc., Bengal, 1975, 29, p.97).
The plant is reported to have antiseptic, anti-dysenteric and anti-tubercular properties. The bark has acrid taste. It is recommended for bronchitis, leprosy, paralysis and helminth infections. The bark and seeds are astringent, useful in piles and diarrhoea, and act as tonic and restorative.
The water extract has been used as a traditional remedy for bronchitis, leprosy, gum inflammations and helminth infections. (Chopra R. N., et al., Glossary of Indian Medicinal Plants, 1956, p.11)
Pharmacology: A decoction of the bark and flowers protects the guinea pig against histamine as well as acetylcholine induced bronchospasm. Prolonged treatment with bark decoction protects the sensitized guinea pigs against antigen challenge. (Tripathy and Das, Indian J. Pharmacol., 1977; 9; p.189). The bark is used as one of the ingredients of an Ayurvedic Kada or decoction used for treating asthma. Pharmacologically it was found to show antitussive action and the ability to prevent allergy-induced bronchospasm. The bark is also useful in the treatment of allergic conjunctivitis. (Iyengar et al, Indian Drugs, 1994, 31, 183, 187; Mukhopadhyay et al, J. Res. Educ. Ind. Med., 1992, 11 (4), p.17). The use of Albizia species decoction in the treatment of allergy is of great interest on several reasons viz., easy availability from natural sources, simple methods of preparation and drug administration and multi pronged activity i.e. inhibition of the sensitization process, anti body synthesis and mast cell degranulation. Anti-anaphylactic activity: Shows the effectiveness of water extract in anti-anaphylactic activity in guinea pig and rats. (Tripathi R. M., et al., Journal of Ethnopharmacol. 1979; 1: p.397-406). The effectiveness of the species of Albizia extract in the induced condition in guinea pigs was studied and its effect was found to be good. Also 60 patients of Bronchial asthma when treated, drop in histamine levels after treatment, was also found to be good (Tripathi S. N., et al., Quart. J. of Surgical Science, 1978, March-June, p.170-176). Atopic Allergy: The effect of extract of species of Albizia on the degranulation rate of peritoneal mast cells of albino rats was studied (Tripathi R. M, et al., Journal of Ethnopharmocol., 1979, 1, p.385-396) and the result was very encouraging.
Phytochemistry: The bark yielded tannins of condensed type, viz., D-Catechin, Lebbecacidin (8,3xe2x80x2,4xe2x80x2-tetrahydroxyflavan 3,4-diol). Isomers of leucocyanidin (5,7,3xe2x80x2,4xe2x80x2-tetrachydroxy flavan -3,4-diol), (xe2x88x92)-melacadidin (7,8,3xe2x80x24,xe2x80x2-tetrahydroxyflavan-3,4-diol) in addition to friederein and xcex2-Sitosterol. (Chatterjee, A., et al., The Treatise of Indian Medicinal Plants, 1992, Vol2, p.61-62). In another study, the bark yielded tannins (7-11%) of condensed type, viz. D-catechin, isomers of leucocyanidin (5,7,3xe2x80x2,4xe2x80x2-tetrahydroxyflavan-3,4-diol) and (xe2x88x92)-melacacidin (7,8,3xe2x80x2,4xe2x80x2-tetrahydroxyflavan-3,4-diol) and a new leucoanthocyanidin, lebbecacidin (8,3xe2x80x2,4xe2x80x2-trihydroxyflavan-3,4-diol). It also gives friedelin and xcex2-sitosterol. Extract of the bark possesses anthelmintic activity and expectorant action. (The Wealth of Asia, NISCOM, D-2.3, CSIR, New Delhi, 1996).
The extracts of the above mentioned plants were then blended in several prototype combinations and each of these combinations were again subjected to the mast cell stabilization assay. The prototype combinations were prepared using the isobologram technique such that the resulting combinations have synergistic antiallergic activity. As per the isobologram technique, increasing concentrations of one ingredient were plotted against the increasing concentrations of another ingredient, as shown in FIG. 1. In this context reference may be made to xe2x80x9cGoodman and Gillman""s xe2x80x98The Pharmacological Basis of Therapeuticsxe2x80x99, Vol. 2, 8th Edition, page 1038, edited by Alfred Goodman Gillman et al., 1992, published by McGRAW-HILL, INC. Singaporexe2x80x9d. Each of these combinations thus prepared were subjected to the mast cell stabilization assay and the synergistic combinations were selected for further compatibility studies with other ingredients.
Based on these studies increasing concentrations of the extracts of Emblica officinals fruits, extracts of Terminalia chebula fruits, extracts of Terminalia bellerica fruits were plotted and tested against increasing concentrations of the extract of Albizia lebbeck bark and each of these combinations were tested in the mast cell stabilization assay. All these permutations and combinations, showed synergism and promising anti allergic activity. Amongst these combinations one of the combination in the ratio of 3:3:3:1 (Emblica officinalis: Terminalia chebula: Terminalia bellerica: Albizia lebbeck) was selected for further development of the invention, which is shown in FIG. 2.
From the table 1 above the remaining ingredients which showed potent mast cell stabilisation activity were selected (viz Piper longum, Piper nigrum and Zingiber officinale) for compatibility studies. It was found that the presence of extracts of the plants Piper longum, Piper nigrum and Zingiber officinale in the composition further enhanced the synergistic activity and the mast cell stabilisation activity of the resultant composition making it useful as antiallergic agent specifically for the treatment of allergic rhinitis and allergic asthma.
Accordingly, the present invention provides an improved synergistic herbal composition having anti allergic activity particularly for the treatment of allergic rhinitis and allergic asthma, which comprises the extracts of:
fruits of Terminalia chebula in an amount in the range of 15-50% w/w
fruits of Terminalia bellerica in an amount in the range of 15-50% w/w
bark of Albizia lebbeck in an amount in the range of 0.5-50% w/w
fruits of Emblica officinalis in an amount in the range of 15-50% w/w
According to another feature of the present invention the above composition also contains the extracts of:
fruits of Piper longum in an amount in the range of 0.1-5% w/w
fruits of Piper nigrum in an amount in the range of 0.1-5% w/w
rhizome of Zingiber officinale in an amount in the range of 0.1-5% w/w
In an embodiment of the present invention the extracts of the plants employed may be water extracts.
In another embodiment of the present invention the extracts of the plants Terminalia chebula, Terminalia bellerica, Albizia lebbeck and Emblica officinalis employed may be water extracts and the extracts of the plants Piper longum, Piper nigrum, and Zingiber officinale employed may be alcoholic extracts.
The above composition of the present invention may also contain pharmaceutical excipients which are usually employed to prepare any oral dosage form like powder, tablets, capsules, syrups and liquids etc.
The excipients such as starch, pre-gelatinized starch, dicalcium phosphate or a mixture thereof may be used. The amount of excipients ranges from 30 to 60% w/w. The composition may also contain preservatives which may be selected from propyl paraben sodium, methyl paraben sodium or bronopol or a mixture thereof. The amount of preservatives employed may ranges from 0.1 to 1% w/w.
According to the present invention there is provided a process for the preparation of an improved synergistic herbal composition having anti allergic activity particularly for the treatment of allergic rhinitis and allergic asthma, which comprises mixing the extracts of
fruits of Terminalia chebula in an amount in the range of 15-50% w/w
fruits of Terminalia bellerica in an amount in the range of 15-50% w/w
bark of Albizia lebbeck in an amount in the range of 0.5-50% w/w
fruits of Emblica officinalis in an amount in the range of 15-50% w/w
and drying the resultant mixture by conventional methods
According to another feature of the invention the extracts of
fruits of Piper longum in an amount in the range of 0.1-5% w/w
fruits of Piper nigrum in an amount in the range of 0.1-5% w/w
rhizomes of Zingiber officinale in an amount in the range of 0.1-5% w/w
are also added to the above said mixture and mixed thoroughly and the drying the resulting mixture.
In a preferred embodiment of the present invention, the drying may be effected by spray drying or by heating at a temperature in the range of 50-70xc2x0 C. under vacuum.
In an embodiment of the invention the extracts of the plants employed for preparing the composition may be water extracts.
In another embodiment of the present invention the extracts of the plants Terminalia chebula, Terminalia bellerica, Albizia lebbeck and Emblica officinalis employed for preparing the composition are water extracts and the extracts of the plants Piper longum, Piper nigrum and Zingiber officinale employed are alcoholic extracts.
The above extracts can be prepared as per the conventional extraction procedures.
The excipients usually used in pharmaceutical preparations, may be added to the mixture to prepare modern dosage forms like tablets, capsules, powder, liquid, syrups etc. The excipients such as starch, pre-gelatinized starch, dicalcium phosphate or a mixture thereof may be used and the amount of excipients used may range from 30 to 60% w/w.
Preservatives may also be added to the mixture which when used may be selected from propyl paraben sodium, methyl paraben sodium or bronopol or a mixture thereof. The amount of the preservatives used may range from 0.1 to 1% w/w.
It would be very clear from the above said description that the composition of the present invention is not a mere admixture of the ingredients used resulting in a composition having the aggregate properties of the ingredients employed. The composition is a synergistic mixture of the ingredients having unique and profound antiallergic activity.
The invention is described in detail in the Examples given below which are provided by way of illustration only and therefore should not be construed to limit the scope of the invention.